Apparatus for the continuous treatment of an advancing web

ABSTRACT

An apparatus for the continuous treatment of an advancing web such as a cotton fabric with one or more reactive gases comprises one or more reaction chambers, each including fluid discharge means for directing a treating gas onto the web in the chamber and evacuation means disposed on both ends of the chamber to prevent both the fluid from escaping from the chamber and the fluid outside the chamber from entering the chamber. Heating means adapted to heat the continuously advancing web of fabric material may also be provided. Suitable heating means include a plurality of heated rotary drums. Such an apparatus may be used for the application of gases such as formaldehyde or sulfur dioxide or both to a cellulose fibercontaining fabric at an elevated temperature and in the presence of controlled amounts of moisture. In this manner, a previously applied N-methylol precondensate can be &#39;&#39;&#39;&#39;wet fixed&#39;&#39;&#39;&#39; in the fabric, thus making it possible to improve the wrinkle resistance and other shape-holding properties of the fabric while preserving good fabric strength after an eventual dry cure. Such a process can also be used directly to impart the desired shape-holding properties to the fabric, e.g., by crosslinking cotton by means of an acid-catalyzed formaldehyde reaction in the described apparatus.

United States Patent [191 Getchell et al.

1 1 Sept. 30, 1975 APPARATUS FOR THE CONTINUOUS TREATMENT OF ANADVANCING WEB [75] Inventors: Nelson F. Getchell, Great Falls, Va.;

Norman R. S. Hollies, Bethesda; Samuel S. Stanton, Chevy Chase, both ofMd.

[73] Assignee: Cotton Incorporated, New York.

[22] Filed: Feb. 2, 1973 [21] Appl. No.: 329,145

Primary E.\'uminerRobert L. Bleutge Assistant Exumim'rPhilip R. Coe

Attorney, Agent, or FirmBurns. Doane, Swecker & Mathis [57] ABSTRACT Anapparatus for the continuous treatment of an advancing web such as acotton fabric with one or more reactive gases comprises one or morereaction chambers, each including fluid discharge means for directing atreating gas onto the web in the chamber and evacuation means disposedon both ends of the chamber to prevent both the fluid from escaping fromthe chamber and the fluid outside the chamber from entering the chamber.Heating means adapted to heat the continuously advancing web of fabricmaterial may also be provided. Suitable heating means include aplurality of heated rotary drums.

Such an apparatus may be used for the application of gases such asformaldehyde or sulfur dioxide or both to a cellulose fiber-containingfabric at an elevated temperature and in the presence of controlledamounts of moisture. In this manner, a previously applied N-methylolprecondensate can be wet fixed" in the fabric, thus making it possibleto improve the wrinkle resistance and other shape-holding properties ofthe fabric while preserving good fabric strength after an eventual drycure. Such a process can also be used directly to impart the desiredshape-holding properties to the fabric, e.g., by erosslinking cotton bymeans of an acid-catalyzed formaldehyde reaction in the describedapparatus.

9 Claims, 4 Drawing Figures US. Patent Sept. 30,1975 Sheet 1 of 33,908,408

U.S. Patent Sept. 30,1975 Sheet 2 of3 3,908,408

US. Patent Sept. 30,1975 Sheet 3 of3 3,908,408

507 A {0 up r S.

APPARATUS FOR THE CONTINUOUS TREATMENT OF AN ADVANCING WEB BACKGROUND orTHE INVENTION Various-processes have been developed for altering thephysical properties of a fabric by applying various agents to thefabric, usually during a finishing process. For example, it iswell-known to impart durable wrinkle resistance to cellulosefiber-containing fabrics such as cotton by impregnation of a continuouslength of fabric with an aqueous solution of a suitable low molecularweight thermosetting resinous precondensate or cellulose crosslinkingagent of a small enough molecular size to penetrate the cellulose fiberstructure, usually with an appropriate catalyst, and eventual curing ofthe impregnated fabric. Such treatments have been effective inimprovingthe shape-holding properties of cotton fabrics and haveresulted in a greatly increased demand for durable press cotton fabricsbecause these combine the traditional comfort, washability and economyof the native fibers with the easy care properties desired in todaystextile market. To facilitate garment manufacture, the cure of suchresin-treated fabrics is delayed until after the treated fabric is cutand sewn to produce the desired finished garment and after such garmentis given the desired shape by pressing.

A particularly promising approach to the production of easy-care,durable press garments has involved the wet fixation of resinorpolymer-forming creaseproofing agents, such as formaldehyde-melamineprecondensates, as disclosed, for example, in US. Pat. No. 3,138,802. Inthis type of process, a fiber system such as a cotton fabric isprotected against excessive strength loss and presensitized for durablepress processing by fixation of a suitable polymer-former andcreaseproofing agent within the fibers while they are wet and swollenbut without greatly altering the dry crease recovery angle or durablepress properties of the fiber system. The latter properties are onlyimparted in the desired degree during a subsequent dry cure. Such aprocess accordingly permits ready creasing or other distinct shaping ofthe fiber system during apparel manufacture or the like subsequent tothe wet fixation step and prior to the delayed dry cure. However, wetfixation processes heretofore known have usually required neutralizationand wash-off of the strongly acid wet fixation catalyst subsequent tothe wet-fixing step, to be followed by drying and then recatalyzationand redrying prior to the actual cure, thus requiring additionalprocessing time and effort.

Other promising approaches to the production of easy care, durable pressgarments have involved exposing a conditioned cotton fabric toformaldehyde and gaseous sulfur dioxide and heating the fabric undercontrolled moisture conditions, as disclosed, for example, in US. Pat.No. 3,706,526, and in copending application Ser. No. 237,056 of Swidleret al. filed Mar. 22, 1972, assigned to the assignee of the presentapplication. These processes result directly in a cured fabric.

A superior durable press process is disclosed in US. Pat. No. 3,642,428.This process includes applying to a cellulose fiber-containing fabric asolution containing a polymer former such as a melamine-formaldehyde orurea-formaldehyde precondensate and a latent curing catalyst.Subsequently, the fabric while in a water swollen state is exposed at anelevated temperature in the presence of formaldehyde to a gas which is astrong acid (e.g., acetic acid, formic acid, hydrogen chloride) orcapable of forming a strong acid by reaction with formaldehyde (as inthe case of sulfur dioxide). The resulting fabric, which now containsthe polymer former 5 wet-fixed therein, is dried to form a fabric whichcontains the wet-fixed resin. This dry fabric may-then be sewn to form agarment which may have creases hot pressed into it and the garment mayfinally be cured in the presence of a latent curing catalyst to impartdurable press properties to it. As an alternative, the fabric containingthe wet-fixed resin and latent catalyst may be cured and thus havedurable press properties imparted to it before it is made into a finalproduct such as bed linen, or, if desired, a garment.

When a durable press fabric is to be directly produced in accordancewith the reaction disclosed in the above-mentioned US. Pat. No.3,706,526, treatment of the fabric with formaldehyde and sulfur dioxidemust be carried out under carefully controlled conditions of temperatureand humidity in order to achieve optimum results as the crosslinkingreaction based on formaldehyde and sulfur dioxide is self-limiting inthat removal of water from the system causes decomposition of the strongsulfonic acid which serves as a catalyst for this reaction. I

Another important consideration in processes of these types is providingsuitable apparatus which prevents leakage of hazardous or noxiousreactants, such as formaldehyde and sulfur dioxide, out of theapparatus. Both formaldehyde and sulfur dioxide are noxious and pungent,and leakage of these materials into the atmosphere around the processingapparatus is objectionable from the point of view of safety orindustrial hygiene. 35

OBJECTS AND SUMMARY OF THE INVENTION Accordingly, it is an object ofthis invention to provide an apparatus for efficiently and effectivelytreating a continuously advancing web of material with noxious orhazardous fluid. I

Another object of the invention is to provide an apparatus for treatinga continuously advancing web of material with a reactive gas undercontrolled conditions of temperature, gas concentration and humidity.

A further object of the invention is to provide an and apparatus fortreating a continuously advancing web of material with a noxious gaswithout objectionable leakage of the gas into the surrounding atmosphereor leakage of the atmosphere into the treating chamber.

A specific object of this invention is to provide an and apparatus forthe wet fixation of a polymer former such as a N-methylol containingprecondensate in a cotton-containing fabric with formaldehyde and sulfurdioxide in the presence of moisture to provide a fabric suitable for thesubsequent formation of a durable press article, whichapparatussubstantially prevent leakage of formaldehyde or sulfur dioxide intoadjacent areas.

Another specific object of this invention is to provide an apparatus forthe reaction of a cellulose fibercontaining fabric with formaldehyde inthe presence of an acid catalyst and moisture to provide a fabric havingdurable press properties, without objectionable leakage of noxious gasinto adjacent areas.

These and other objects of the invention will become more clearlyapparent from the following description.

In accordance with the invention, there is provided a fluid treatmentapparatus comprising: enclosure means; first and second reaction chambermeans in said enclosure means for applying fluid to a continuous web ofmaterial being conducted therethrough; a plurality of rotary drums insaid enclosure means between said first and second reaction chambers;and means for conducting a continuous web of material into saidenclosure and in sequence through said first reaction chamber and oversaid rotary drums and through said second reaction chamber, andsubsequently out of said enclosure.

By carrying out contact of the fabric with treatment gases within thefluid treatment apparatus of the present invention, the fabric may betreated under controlled conditions without significant leakage ofhazardous or noxious gases into the interior of the enclosure to poseasafety hazard or interfere with intermediate processing steps which arebeing performed within the same enclosure.

These and other aspects, advantages and embodiments of the presentinvention will become more clearly apparent from the following detaileddescription.

DESCRIPTION OF THE DRAWINGS DESCRIPTION OF THE PREFERRED EMBODIMENT TheApparatus A preferred embodiment of the fluid treatment apparatus ofthis invention is illustrated schematically in FIG. 1. The apparatusincludes an enclosure which is in the form of a large box. The top andbottom walls, side walls, and end walls of the enclosure 10 may bejacketed in order to minimize heat conduction through the walls. The webor fabric 14 enters the enclosure 10 through a horizontal slot 16 whichextends across at least a portion of the end wall of the enclosure 10.Preferably, inwardly curved guide members, as indicated schematically at16, are positioned in close proximity to the upper and lower surfaces ofthe fabric to minimize heat loss from the interior of the enclosure.

A reaction chamber 12 is mounted in the interior of the enclosure 10adjacent one end (preferably the fabric entry end). The reaction chamber12 has openings at the top and bottom to allow the fabric 14 to passthrough the chamber 12. Reaction chamber 12 is suitably provided withfluid inlet and outlet means, as more fully explained hereinbelow, toprovide contact between the fluid and the fabric within the reactionchamber 12. The enclosure 10 further contains guide rolls 18 disposed atthe top and the bottom of the reaction chamber 12 which align the fabric14 with a center plane passing vertically through the reaction chamber12.

From the reaction chamber 12, the fabric is guided by suitably disposedguide rolls 19 over a plurality of heated rotary drums 20. The drums 20are of conventional construction and may be provided with suitable meansfor heating the surface of the drums to temperatures in the rangebetween and C. The size and number of the drums 20 as well as the speedof the fabric about the drums may be adjusted such that the fabric isheated to a desired temperature as the fabric 14 exits from the drums20.

A second reaction chamber 22, which is substantially identical inconstruction to the reaction chamber 12, may be mounted verticallywithin the enclosure 10. Guide rolls 24 are provided in enclosure 10 forguiding the fabric 14 through the reaction chamber 22 in the same manneras the guide rolls 18.

The enclosure 10 also may include suitable means to provide, if desired,an area for the fabric to be held for a desired time prior to leavingthe enclosure 10. For example, a plurality of guide rolls 26 may bearranged along the top and the bottom of the enclosure and the fabric 14passed over these guide rollsto allow exposure of the fabric to theconditions in the enclosure for a predetermined period of time as thefabric advances continuously. Preferably, one or more heating means 28extending across the width of the enclosure 10 on opposite side ofvertical runs of the fabric may be provided. Other suitable means toprovide a desired temperature or moisture content, such as steam jets orthe like, in the enclosure may also be provided. Gas may be withdrawncontinuously through one or more conduits 30 along the top of theenclosure 10. This controlled exhaust arrangement permits keeping thesystem at a predetermined negative pressure relative to the exteriorpressure. The fabric 14 may be removed from the enclosure 10 throughhorizontal slot 14 for further pro cessing.

The reaction chamber 12 is illustrated in FIGS. 2, 3 and 4. The endwalls and top and bottom walls of the chamber 12 are formed by arectangular frame 32. Side panels 34 are secured to the frame 32 andsealed against leakage around the edges of the panel. Brackets 36 may beprovided on the frame for mounting the reaction chamber 12 in theenclosure 10.

Reaction chamber 12 includes one or more conduits or spray members whichmay be in the form of one or more pipes 62 extending the width of thereaction chamber 12 and preferably equidistantly disposed on oppositesides of the central plane 66 which passes midway between the panels 34.The plane 66 coincides with the path of the fabric 14 as it passesthrough the reaction chamber 12.-Each spray member has a series ofregularly spaced openings 64 which form nozzles for directing the fluidout of the pipe into the reaction chamber. Preferably the nozzles aredirected to discharge the fluid towards the .central plane 66. Thesleeve-like chamber 12 and the spray members 62 are arranged to providepenetration of the fluid throughout the fabric as the fabric passesthrough the chamber. Penetration is provided by a number of factorsincluding, for example, the relative thinness of the reaction chamber12, the number and position of the nozzles and the velocity of the fluidexiting from the nozzles.

Each panel 34 may have a thin plate heat exchanger 38 mounted on theinterior wall by means of studs 40. The heat exchangers 38 are providedwith pipe fittings 42 which extend through the panels 34 for conductingheat transfer fluid into and out of the heat exchangers 38. Preferably,each heat exchanger 38 also has a convoluted surface on at least theside adjacent the fabric sufficient to promote turbulent flow of a fluidalong the fabric surface after the fluid has been introduced throughopenings 64. Such turbulent flow also provides penetration of the fluidthroughout the web.

As shown in FIG. 4, the top and bottom of the frame 32 have slots 44which extend from one end of the frame 32 to the other. The oppositeedges of the slots 44 may be covered by lip member guide means which maybe flexible, semicircular lengths of a suitable nonreactive material.Characteristically, lip members 46 are formed from plastic (e.g.,polytetrafluor'oethylene) tubing which has been cut in half and mountedon the top and bottom of the frame by means of screws or other suitablemounting means. I

A wind box 48 is mounted over each of the slots 44 and is secured andsealed to the frame 32. Each wind box 48 includes a pair of plenumchambers 50 on opposite sides of the slot 44. Each plenum chamber 50 iscoextensive with the width of the frame 32. An end plate 52 is securedbetween the plenum chambers 50 at opposite ends of the slot. A coverplate 54 is also mounted on each pair of plenum chambers 50 and extendsthe width of the chamber. The cover plate 54 and the end plates 52 andthe opposite walls of the plenum chambers 50 cooperate to form anenclosure around the slot 44 at the top and the bottom of the frame 32.The cover plate 54 has a longitudinal slot 56 which is aligned with andsubstantially coextensive with the corresponding slot 44.

The plenum chambers 50 each contain exhaust apertures such as aplurality of holes 58 spaced apart at regular intervals along the lengthof the slot 44. The plenum chambers are each connected via exhaust pipe60 to suitable exhaust means (now shown) such as a suction fan whichprovides a sufficient exhaust such that any gas or vapor leaking throughthe slots 44 will be effectively drawn out through the exhaust apertures58 and will not enter the interior of the enclosure 10. Since the gas iswithdrawn before it can enter the enclosure 10, it cannot leak from theenclosure into the area adjacent thereto. The reaction chamber 12 ismaintained at a predetermined negative pressure relative to the pressurewithin the enclosure Also, gas which may be in the enclosure (e.g., air,steam) is withdrawn through exhaust apertures 58 before such gas canenter through slots 44 into the interior of the reaction chamber 12.

As noted before, reaction chamber 22 may be identically constructed asreaction chamber 12.

Although the fluid treatment apparatus of the present invention has beenillustrated in FIG. 1 and the accompanying description as including tworeaction chambers, it will be understood that other embodiments of theapparatus of the present invention may also include only one or morethan two such reaction chambers.

Processing The fluid treatment apparatus of the present invention isparticularly well-suited for use in durably fixing a polymer former or acrosslinking agent in a cellulose fiber-containing fabric in acontinuous manner. This fixation can make the fabric capable ofdeveloping durable press properties when subsequently dry cured, or, inthe case of suitably chosen reaction system, the fixation itself canimpart the desired durable press properties to the fabric.

In one embodiment of such a process, the fabric which is continuouslyadvanced into the enclosure is a cellulose fiber-containing fabric whichhas been padded with an aqueous solution containing a latent curingcatalyst and a water-soluble polymer-forming material such as anaminoplast precondensate containing reactive N-methylol groups or acompound such as urea which forms a N-methylol precondensate uponreaction with formaldehyde. The padded fabric is exposed in the presenceof moisture to formaldehyde and sulfur dioxide at a temperaturesufficient to cause the N- methylol compound and formaldehyde to becomedurably fixed in the material in substantially water insoluble form soas to be capable of causing the desired crosslinking during a final drycure step.

The fabric may contain various natural or regenerated cellulose fibersalone or as mixtures with each other in various proportions or asmixtures with other fibers. They include natural cellulose fibers suchas viscose rayon and cuprammonium rayon. Other fibers which may be usedin blends with one or more of the above-mentioned cellulosic fibers are,for example, wool, silk, cellulose acetate, polyamides (e.g., nylon),polyesters (e.g., polyethylene terephthalate), acrylics, polyolefins(e.g., polypropylene), polyvinyl chloride, polyvinylidene chlorine, andpolyvinyl alcohol fibers. Such blends may include at least 15 percent,desirably at least 35 percent, but most preferably at least percent, ofcotton or other natural cellulose fiber.

The material may be a knitf'woven, nonwoven, or otherwise constructedfabric or the invention may be applied to fibers or yarns before theyare converted into more complex structures. The web may be in flat,creased, pleated or hemmed form prior to treatment in the presentinvention and may be formed into virtually any shape after being wetfixed in accordance with the present invention. After completeprocessing, the formed crease-proofed fabric will maintain the desiredconfiguration substantially for the life of the article, that is, adurable press fabric will be produced which will retain its desiredshape through numerous wearwash-dry cycles, requiring little or nopressing. The process may also be applied to paper to increase its wetstrength and durability.

The preferred polymer-forming N-methylol compounds at this time includethe melamineformaldehyde, urea-formaldehyde, and the phenolformaldehydeprecondensates.

The polymer formers useful herein include particularly the easilyhardenable precondensates which are substantially water soluble and areobtained by condensation of formaldehyde with a compound such asmelamine or a C to C alkyl substituted melamine, a urea, or a hydroxybenzene such as phenol or resorcinol. The resulting methylol-containingcompound or precondensate may further be etherified by reaction with alower alkanol such as methanol or butanol. As is well known in thefabric treating art, these precondensates are capable of being appliedto the cellulosic material from an aqueous solution and to be readilywet fixed or insolubilized therein as described, for instance, in USPat. No. 3,138,802. Triazines obtained by condensing a methyl or otherlower alkyl substituted melamine and formaldehyde are further examplesof such precondensates.

Good results are obtained, for instance, using precondensates obtainedby condensing 1 mole of melamine or an alkyl substituted melamine with 2to 6 moles of formaldehyde, i.e., using di-, tri-, tetra-, penta-, orhexa-methylol melamine. Such products function well as polymer formerswhich can be readily wet fixed in the material by heating or steaming asdescribed herein.

Commercially available products of this kind include Aerotex 23, analkylated melamine-formaldehyde precondensate; Aerotex M-3, adimethoxymethylhydroxymethyl-melamine; and Aerotex 19, which is a lesscompletely fractionated modification of Aerotex P- 225. These productsare supplied in the form of aqueous solutions by American CyanamidCompany. Equivalent products are commercially available from othermanufacturers.

The padding bath with which the fabric is contacted generally alsocontains a conventional latent curing catalyst which releases or acts asa strong acid upon heating to an elevated temperature such as 120C orhigher. For example, one can use a water-soluble salt of a strong acidwith a weak base such as an ammonium salt of hydrochloric, sulfuric,nitric, oxalic, lactic, or other inorganic or organic acid, variousamine hydrochlorides, as well as acid acting salts of metals such aszinc or magnesium, e.g., zinc nitrate or magnesium chloride or a mixedcatalyst such as MgCl /ZnCl MgCl /citric acid or Zn(NO /tartaric acid.

For example, when using conventional padding equipment, or when applyingthe chemicals by spraying or other known processes, the polymerizable N-methylol compound or precondensate may be dissolved in water to form asolution containing from about 3 to 25 percent, and preferably fromabout 5 to percent, of the N-methylol compound. To facilitate itsultimate cure in the cellulosic material, a curing catalyst may beincluded in this same solution, or in a separate solution, in an amountof between about 1 and 10 percent, and preferably between about 4 and 6percent, based on the weight of the N-methylol compound. As known tothose skilled in the art, the optimum concentration depends somewhat onthe particular catalyst and particular N-methylol compound used, and maybe determined by routine preliminary tests.

Depending on the requirements of the finished materials or fabrics, thepadding or impregnation is carried out in such a manner that the addonof N-methylol compound deposited on the material is between about 3 and12 percent, and preferably between about 6 and 8 percent, calculated asdry solid deposit based on the weight of dry fibrous material (owf").The padding is normally performed at ambient temperature, e.g., betweenabout 10 and 30C.

The aqueous padding bath may also contain other conventional fabrictreating agents, for instance, wetting agents and fabric softners, i.e.,polymers capable of forming a soft film on the material or fabric. Forexample, suitable fabric softeners include a latex or fine aqueousdispersion of polyethylene, various alkyl acrylate polymers,acrylonitrilebutadiene copolymers, deacetylated ethylene-vinyl acetatecopolymers, polyurethanes, and the like. Polymeric additives suitablefor this general purpose are otherwise well known in the art and in mostcases are commercially available in concentrated aqueous latex form. Foruse in the present invention, such a dispersion is preferably diluted toprovide about 0.1 to 4 percent of softener based on the weight of thefabric (owf).

After padding in the liquid bath containing the polymer-former, it isgenerally useful to pass it between squeeze rolls where excess liquid issqueezed out.

The paddedsqueezed fabric enters the enclosure 10 at ambient temperatureand is passed about guide rolls into and through a first reactionchamber 12. The enclosure 10 is maintained at a reduced pressurerelative to ambient, such as, for example, about 0.1 to 1.0 in.

water gauge below ambient. An acid such as sulfur dioxide gas ispassedinto the reaction chamber 12 and impinged through pipes 62 andopenings 64 onto the continuously advancing fabric. Reaction chamber 12further contains a thin-walled, convoluted surface heat exchange 38through which cooling fluid is passed to maintain the fabric temperatureat about ambient (e.g., from about 20 to about 50 C., preferably fromabout 25 to about 40 C.). Turbulence is promoted by the velocity of thefluid impinged through openings 64 and the convoluted surface enhancesturbulent flow of the treating gas as it passes over the fabric thuspromoting solid-vapor contact As understood by those skilled in the art,laminar flow of a gas along a solid surface is generally accompanied bya boundary layer which retards contact of the vapor and the solid.Baffles or other turbulence promoting structures may also be utilized.

A negative pressure relative to the pressure within enclosure 10 ofabout 0.5 to about 1.0 in. water gauge, preferably from about 0.5 toabout 0.8 mm. Hg, is created through exhaust pipe 60 to plenum chambers50 at each end of the reaction chamber 12. In this manner, leakage oftreating gas from the interior of reaction chamber 12 into the enclosure10 is substantially prevented.

The fabric is continuously advanced from reaction chamber 12 about guiderolls 19 over five rotary drums 20 each heated to a temperature of aboutto about 200 C., preferably from about to about 180 C, to heat thefabric rapidly to the desired temperature with a minimum loss ofmoisture.

The heated fabric is continuously advanced over guide rollers 24 intoand through a second reaction chamber 22. Formaldehyde vapor is impingedonto the fabric at a temperature of about to about 200 C, preferablyfrom about to about 180 C. Heated fluid may be passed through a thinplate, convoluted surface heat exchanger of the same construction as inreaction chamber 12 to maintain the desired temperature within theinterior of the reaction chamber 22 as well as to promote vapor-solidcontact.

As understood by those skilled in the art, and as more fully explainedin US. Pat. No. 3,642,428, herein incorporated by reference, themoisture content of the fabric in the second reaction chamber isimportant and is maintained between about 15 and about 90, preferablybetween about 30 and about 70 percent by weight of the fabric. Themoisture content is important as water reacts with the S0 andformaldehyde to form a strong acid catalyst in situ on the fabric inaccordance with the following reversible equation:

CH O S0 H O HOCH -SO H This strong acid catalyst fixes the polymer inthe fibers of the fabric, and can then be decomposed by simple drying. I

Again, a reduced pressure of the same magnitude as applied to the plenumchambers of reaction chambers After leaving the second reaction chamber22, the

fabric may be continuously advanced-about a plurality of guide rolls 26in the holding area of the enclosure 10 for a time and at a temperaturesufficient to essentially complete the polymerization and fixation 'ofthe'polymer-former in the fabric.

The fabric is removed from the enclosure 10 and may be further processedto form a durable press article. After exposure to the reactiveatmosphere in the second reaction chamber, if the initial pad bathcontained a latent curing catalyst, the cellulosic materialis directlydried in preparation-for the manufacture of a durable press articletherefrom. No other intervening rinsing or other processing is requiredin 'such a case. Only if a latent catalyst was not included in theinitial pad bath is it necessary to pass the fabric after the vaportreatment and before the drying step through a second pad bathcontaining an aqueous solution of a suitable latent curing catalyst,whereby the fabric becomes catalyzed for the eventual dry'cure. Dryingcondition'sfa're not especially critical, but if delayed cure propertiesare desired, drying should be controlled to avoid precuring. I y

In a specific embodi ment ofthe invention, a continuous length of a 100percent cotton fabric is padded with an aqueous solution of 12 percentof hexakis (methoxymethyl) melamine precondensate, 0.5 percent zincnitrate hexahydrate, 0.2 percent Triton X-l nonionic wetting agentand'l.0 percent finely dispersed polyethylene fabric softener (Velvamine732").

After squeezing out excess liquid to a 65 percent wet pick-up by passagethrough a pair of squeeze rolls, the fabric is continuously advancedinto the enclosure as shown in FlG. 1.

v The fabric is continuously advanced into a first steel reactionchamber which is wider than the fabricwidth, long enough to providesufficient contact area between the fluid and fabric and sufficientlyshallow (e.g., about 6 inches or less) to promote penetration of thefluid throughout the fabric. The reaction chamber also includes a sloton its top and bottom extending substantially the width of the reactionchamber.

A wind box is attached to each end of the reaction chamber and also isformed of steel. Each wind box contains a slot in alignment with thecorresponding slot in the reaction chamber. Each wind box plenumchamberfurther includes a plurality of holes arranged symmetrically andequidistant along the length of the slot. One end of each wind boxplenum chamber is provided with a suitable pipe connection to a suctionfan to establish a reduced pressure in the plenum chamber of about 0.5in. water gauge below the pressure in enclosure 10.

The reaction chamberfurther includes a pair of spray members formed ofpipe, each containing a plurality of small diameter holes spacedequidistantly over the pipe length. The reaction chamber also includes aconvoluted surface thin plate heat exchanger on either side of thefabric with suitable connections to a cooling fluid source.

Sulfur dioxide gas is passed into the spray pipes an is impinged on thefabric continuously advancing there through while sufficient water ispassed through the heatexchangers to maintain the fabric temperature atabout 25C.-

, The fabric is continuously advanced from the first reaction chamberabout five rotary drums which may be independently heated totemperatures ranging from to.2 00 C. by steam in the interior of thedrums.

The fabric, at the desired temperature, is passed into a second reactionchamber constructed in the same manner as the first reaction chamber,where formaldehyde vapor is impinged on the fabric. Steam is passedthrough the heat. exchangers to maintain a temperature in the reactionchamber of about 150C. The fabric has a moisture content of about 50percent (owf) to polymerize the resin and cause it and the formaldehydeto become fixed in the fabric, leaving the fabric capable of beingcrosslinked in a subsequent dry cure step.

The treated fabric leaves the second reaction chamber and. is guidedabout the holding area atime sufficientto complete fixation of the resinand formaldehyde in the fabric. During this time, which may be about oneminute or. less, the heat exchangers maintain a temperature of about C.The resulting fabric leaving the enclosure has a moisture content ofabout 45 percent and may be dried. The dried fabric is subsequently drycured to provide a durable press article.

It will be understood that the fluid treatment and arrangement describedabove may be modified in various ways. For example, the padded, squeezedfabric may be passed into the-enclosure 10 and directly about aplurality of heated drums 20 to .raise the temperature of the fabric upto about C. The heated fabric may then be passed into the reactionchamber 22 in which a mixture of formaldehyde and S0 is impinged uponthe fabric at a reaction chamber temperature of from about 75 to about175, preferably from about 90 to about ,C. and a moisture content ofabout 15 to about .90, preferably from about 30 to about 70, percentbyweight of thefabric.

In another embodiment, when ahighly methylolated polymer former is used,such a compound may, in and of itself, furnish sufficient formaldehydeto form the re- .quired amount of sulfonic acid catalyst and assist inthe fixation of formaldehyde in the fabric, and in such a case onlyasingle reaction chamber with proper moisture control is necessary.

Also, the holding portion of the enclosure may be omitted, if desired.The apparatus of the present invention is also useful in a process suchas that disclosed in previously mentioned US. Pat. No. 3,706,526 inwhich an unpadded cotton-containing fabric is contacted with hotformaldehyde and S0 in the presence of moisture to'form the highly acidsulfonic acid catalyst as explained above and cause the formaldehyde tocrosslink the cellulose fibers. The fabric may be heated by passageabout a plurality of rotary heated drums and passed into a singlereaction chamber into which formaldehyde, SO and steam are injectedeither as a mixture or separately. Alternatively, the fabric may bepassed into a first reaction chamber where it is contacted with aformaldehyde-sulfur dioxide mixture and then passed over the rotarydrums into a second reaction chamber where it is heated whilecontrolling the moisture content of the fabric to produce the desiredreaction. The apparatus of the present invention may be utilized in aprocess for imparting flameproofing properties to cellulosefiber-containing fabrics in which, for

example, the fabric is padded with an aqueous solution of monomeric tris(hydroxymethyl) phosphine and dried to a wet pick-up of about 12 to 15percent. The fabric is then passed into a single reaction chamber inwhich ammonia gas is impinged onto the fabric at ambient temperature todeposit within and on the fabric a polymerized phosphorus-containingmaterial.

This apparatus is similarly useful in a process for imparting durablepress properties to a fabric in the presence of a gaseous catalyst, suchas, for example, passing a cellulose fiber-containing fabric padded withan aqueous solution of a water-soluble crease-proofing agent containingreactive N-methylol groups over the heated rotary drums to a temperatureof between above 80 up to about 160C. and passing the fabric into areaction chamber containing a vapor atmosphere containing a formic acidor acetic acid catalyst to effectively crosslink the cellulose fibers.The crosslinked fabric may be further heated in the enclosure to atemperature above about 100C. to dissipate water vapor, residualcatalyst and unbound crease-proofing agent and to cure the crosslinkedfabric.

While the foregoing specification describes the general principles andnature as well as preferred embodiments and modifications of the presentinvention, still other modifications may be made by those skilled in theart without departing from the scope and spirit of the appended claims.

All parts, proportions and/or percentages referred to in the presentspecification and claims are by weight unless otherwise indicated.

What is claimed is:

l. Fluid treatment apparatus comprising:

enclosure means;

first and second reaction chamber means in said enclosure means forapplying fluid to a continuous web of material being conductedlongitudinally therethrough, said reaction chambers includinglongitudinally aligned entrance and exit openings and means at theentrance and exit openings for preventing significant leakage of thefluid from said chamber into said enclosure means, whereby fluid issubstantially confined within said reaction chamber means, each saidreaction chamber being spaced from the top and botton of said enclosuremeans;

a plurality of rotary drums in said enclosure means between said firstand second reaction chambers;

and

means for conducting a continuous web of material into said enclosuremeans and in sequence through said first reaction chamber and over saidrotary drums and through reaction chamber, and subsequently out of saidenclosure means.

2. The apparatus according to claim 1 wherein said first and secondreaction chambers each include a pair of vertically arranged wallsspaced apart from eadh other, and include means forming a fluid chamberbetween said walls and means for conducting fluid into said chamber.

3. Fluid treatment apparatus comprising:

enclosure means;

first and second reaction chamber means in said enclosure means forapplying fluid to a continuous web of material being conductedtherethrough, said reaction chambers including means for conductingfluid into said fluid chamber and means for conducted into said reactionchamber is caused to flow in turbulent flow along the length of the webadvancing through the chamber, said means for conducting a continuousweb of material includinng guide roller means arranged to conduct saidweb longitudinally along said convoluted heat exchange surface and inclose proximity thereto;

a plurality of rotary drums in said enclosure means between said firstand second reaction chambers; and

means for conducting a continuous web of material into said enclosureand in sequence through said first reaction chamber and over said rotarydrums and through said second reaction chamber, and subsequently out ofsaid enclosure.

4. The apparatus according to claim 2 wherein each of said reactionchambers includes an upper and lower end wall having a longitudinal slottherein, and includes a pair of partitions in said reaction chamberspaced inwardly from said top and bottom end wall, and includes meansfor conducting fluid from the space between said end wall and saidpartition to the exterior of said enclosure.

5. The fluid treatment apparatus of claim 1 wherein diverse fluids areintroduced into the reaction chamber means.

6. An apparatus for treating cellulose fibercontaining fabric with areactive gaseous fluid comprising:

an enclosure;

first and second reaction chambers contained within said enclosure, eachreaction chamber having an entrance opening and an exit opening;

each said reaction chamber including a fluid treat ment chamber havingmeans for providing gaseous fluid contact with at least one surface of afabric passing therethrough and gaseous fluid removal means mountedadjacent to each said entrance opening and exit opening, said gaseousfluid removal means having means for allowing fabric to enter and exitsaid fluid treatment chamber without substantial leakage of gaseousfluid from saidfluid treatment chamber into said enclosure;

a plurality of rotary drums in said enclosure means between said firstand second reaction chambers; and

guide means within said enclosure for continuously advancing a fabricwithin said enclosure, through said reaction chambers and over saidrotary drums and out of said enclosure.

7. The gaseous fluid treatment apparatus of claim 6 wherein said rotarydrums are heated.

8. The gaseous fluid treatment apparatus of claim 7 wherein at least oneof said reaction chambers further includes a plurality of heat exchangermeans.

9. The gaseous fluid treatment apparatus of claim 8 wherein each saidreaction chamber further includes a plurality of fluid inlet meansdisposed to provide fluid on either side of a fabric continuouslyadvancing therethrough and heat exchanger means in said at least onereaction chamber includes a convoluted surface whereby fluid providedthrough said fluid inlet means is promoted to flow along the fabric in aturbulent flow. =l k

1. Fluid treatment apparatus comprising: enclosure means; first and second reaction chamber means in said enclosure means for applying fluid to a continuous web of material being conducted longitudinally therethrough, said reaction chambers including longitudinally aligned entrance and exit openings and means at the entrance and exit openings for preventing significant leakage of the fluid from said chamber into said enclosure means, whereby fluid is substantially confined within said reaction chamber means, each said reaction chamber being spaced from the top and botton of said enclosure means; a plurality of rotary drums in said enclosure means between said first and second reaction chambers; and means for conducting a continuous web of material into said enclosure means and in sequence through said first reaction chamber and over said rotary drums and through reaction chamber, and subsequently out of said enclosure means.
 2. The apparatus according to claim 1 wherein said first and second reaction chambers each include a pair of vertically arranged walls spaced apart from each other, and include means forming a fluid chamber between said walls and means for conducting fluid into said chamber.
 3. Fluid treatment apparatus comprising: enclosure means; first and second reaction chamber means in said enclosure means for applying fluid to a continuous web of material being conducted therethrough, said reaction chambers including means for conducting fluid into said fluid chamber and means for preventing significant leakage of the fluid from said chamber into said enclosure means, whereby fluid is sUbstantially confined within said reaction chamber means, said reaction chamber means each including a heat exchanger in each of said fluid chambers, said heat exchangers extending vertically along said walls and having a generally convoluted heat exchange surface whereby said fluid conducted into said reaction chamber is caused to flow in turbulent flow along the length of the web advancing through the chamber, said means for conducting a continuous web of material includinng guide roller means arranged to conduct said web longitudinally along said convoluted heat exchange surface and in close proximity thereto; a plurality of rotary drums in said enclosure means between said first and second reaction chambers; and means for conducting a continuous web of material into said enclosure and in sequence through said first reaction chamber and over said rotary drums and through said second reaction chamber, and subsequently out of said enclosure.
 4. The apparatus according to claim 2 wherein each of said reaction chambers includes an upper and lower end wall having a longitudinal slot therein, and includes a pair of partitions in said reaction chamber spaced inwardly from said top and bottom end wall, and includes means for conducting fluid from the space between said end wall and said partition to the exterior of said enclosure.
 5. The fluid treatment apparatus of claim 1 wherein diverse fluids are introduced into the reaction chamber means.
 6. An apparatus for treating cellulose fibercontaining fabric with a reactive gaseous fluid comprising: an enclosure; first and second reaction chambers contained within said enclosure, each reaction chamber having an entrance opening and an exit opening; each said reaction chamber including a fluid treatment chamber having means for providing gaseous fluid contact with at least one surface of a fabric passing therethrough and gaseous fluid removal means mounted adjacent to each said entrance opening and exit opening, said gaseous fluid removal means having means for allowing fabric to enter and exit said fluid treatment chamber without substantial leakage of gaseous fluid from said fluid treatment chamber into said enclosure; a plurality of rotary drums in said enclosure means between said first and second reaction chambers; and guide means within said enclosure for continuously advancing a fabric within said enclosure, through said reaction chambers and over said rotary drums and out of said enclosure.
 7. The gaseous fluid treatment apparatus of claim 6 wherein said rotary drums are heated.
 8. The gaseous fluid treatment apparatus of claim 7 wherein at least one of said reaction chambers further includes a plurality of heat exchanger means.
 9. The gaseous fluid treatment apparatus of claim 8 wherein each said reaction chamber further includes a plurality of fluid inlet means disposed to provide fluid on either side of a fabric continuously advancing therethrough and heat exchanger means in said at least one reaction chamber includes a convoluted surface whereby fluid provided through said fluid inlet means is promoted to flow along the fabric in a turbulent flow. 